In my field, I honestly can't think of a scenario I wouldn't want to use an SG switch. Even if someone needed a simple desktop switch, I would advise they purchase a $150 8 port SG350 over spending $50 on a SOHO Netgear or similar switch. The flexibility of functionality offered by these switches in unmatched.
If you've got a large network and are already using FortiGate firewalls or FortiAP access points, integrating FortiSwitch Secure Access Switches makes for one integrated solution. Previously we had Cisco switches that had to be configured and managed separately, which was always prone to error. Now that we have our entire network backbone on FortiNet devices, managing and configuring them is smoother. We are now able to see much clearer if there are any configuration issues between networking devices.
The web UI has taken a turn for the worse with the latest firmware on the SGx50 models -- the bifurcation between basic and advanced modes and the changes to the way VLANs are modified is a step backward in my opinion.
The power bricks on smaller models are enormous. I'm sure, however, keeping this circuitry external to the switch is what keeps my switches running year after year in hot environments.
Fans can be a bit loud on larger switches -- this is true of pretty much any 1U device though.
Cisco Ethernet Switches are top tier in the networking space. It makes it hard at times to compare them to other brands. When I have, however, used other brands I have found them to a mixed bag. I have used HP switches in the past and I feel like the interface is less polished and I have had high failure rates among those devices. It was hard to learn the interface and I felt as thought it was missing some higher level functions that were present out of the box with the Cisco switches.
We have previously used both Cisco 220 Series and Dell PowerConnect 8000 Series switches that were managed separately from our firewalls and access points. The Cisco and Dell switch worked fine and we never had a problem with them, but it was always a hassle to have to make configuration changes since that would have to be done via separate GUIs. Having the ability to configure and manage firewalls, switches, and wireless access points all within one central GUI saves time and headache.